fixes issue 912 + pass proper var to generate aux callstack
fixes issue 912
+ pass proper var to generate aux callstack

git-svn-id: fe3cd4388a6e5a968b09397a3d721fe124e8117a@888 5b54908e-ead4-fc18-b48a-0285e6dbc711

rnk/drmemory,rnk/drmemory,rnk/drmemory,rnk/drmemory